A mana ability is an ability that (1) could add mana when it resolves, (2) isn't a loyalty ability, and (3) doesn't require a target.

The copy will have the same targets as the ability it's copying unless you choose new ones. You may change any number of the targets, including all of them or none of them. If, for one of the targets, you can't choose a new legal target, then it remains unchanged (even if the current target is illegal).

Activated abilities are written in the form "Cost: Effect." Some keywords are activated abilities and will have colons in their reminder texts.

If the ability is modal (that is, it says "Choose one —" or the like), the copy will have the same mode. You can't choose a different one.

If the ability has in its cost, the value of X is copied.

If paying the activation cost of the ability includes sacrificing Kurkesh, the ability won't be copied. At the time the ability is considered activated (after all costs are paid), Kurkesh is no longer on the battlefield.